Validating Confirmation in Vaccine Effectiveness

"What  it shows is that if you're vaccinated you'll definitely be in the minority of people who end up with an infection, end up in hospital or end up dying."

"It 's the prevention of bad outcomes like death that the vaccine does an amazing job at, upwards of 90 to 95 percent."

"The rate of infections in vaccinated people is extraordinarily low ... and you're not taking into account that it was a much larger number that contributed to those infections."
"That leaves about 46 percent or so who are people who are eligible for the vaccine, but aren't vaccinated yet. Getting that population -- the ones who are eligible and easily vaccinated -- would go a long, long way [to reaching a state of herd immunity]."

"There's a strong argument that 50 and older is where we want to look as we have enough vaccine [to administer the third, 'booster' dose for maximum efficacy against COVID]."

"Obviously the most important thing is to get everyone vaccinated. That's No.1, but we're reaching a threshold where trying to [reach] that further bit is difficult."

Dr.Gerald Evans, infectious-disease specialist, Queen's University, Kingston

Drive-thru clinic,Kingston.  CP/Lars Hagberg

According to a newly published study from Public Health Ontario, unvaccinated people account for 90.9 percent of all COVID-19 hospitalizations in the province, and 90.2 percent of all deaths due to the coronavirus. Fully vaccinated people in SARS-CoV-2 breakouts account for a mere 2.7 percent of hospitalizations and 3.3 percent of deaths, according to the report's data. The study represents the most detailed investigation yet of the effectiveness of the     COVID-19 vaccines, both at preventing infections and in limiting severe outcomes.

Data was examined from December 14, 2020 when the first vaccinations were rolled out in the province -- until November 14, including early stages of booster doses for the most vulnerable people in the province. Unvaccinated individuals, measured in the 30 days before the release of the study, were 4.8 times more likely to contract COVID than were fully vaccinated people, according to the study results.

Making up 91.7 percent of all COVID-19 cases in the province, those who remain unvaccinated obviously receive the brunt of the casualties of COVID infections. Infections that hit fully vaccinated individuals -- known as "breakthrough cases" account for only 3.8 percent of infections, with fewer than 0.2 percent of infections occurring in people having received a third dose of vaccine. 

 

Among people aged 60 and over, data are particularly alarming; in that age group those unvaccinated are over 16 times likelier to end up in hospital, as opposed to someone who is fully vaccinated. Seniors for the most part who have received a third dose -- which encompasses those over age 70, the immunocompromised and their caregivers at this juncture -- account for less than 0.2 percent of hospitalizations and under 0.1 percent of deaths.

 

"Yes, you could get infected if you're fully vaccinated, particularly if you're hanging out with someone who is infected and unvaccinated -- and that's what we're beginning to see because there is more soci8alizing going on since we're all desperate for it. But we know that the ultimate outcome is not going to be as bad", advised Dr.Evans. Of 11,154,162 Ontarians fully vaccinated by mid-November, 17.596 had undergone a breakthrough infection. 

 

Current vaccination rate in the province stands at about 78 percent of the entire population. Children aged five to 11 represent roughly 30 percent, with eligibility to receive pediatric doses of the Pfizer-BioNTech vaccine just ratified. Under age four children are not eligible for inoculation, accounting for about 15 percent of the unvaccinated.

 

Experience in Israel and some parts of the United States provide reliable evidence of the utility in expanding the third, booster dose of vaccine to the over-50 group: "Over age 50, you start to see a benefit to third doses", Dr.Evans explained.

 

Breakthrough COVID Infections in Vaccinated

"Vaccines may slow spread -- yes. But many policies across [the] U.S. and elsewhere assume vaccines totally prevent spread."

"This leads to outbreaks among vax'd -- which ultimately erodes trust in the whole vaccine effort unless the expectations are set properly."

Michael Mina, epidemiologist, Harvard University

"In a lot of cases there may be a vast, historical context behind all these feelings and reasoning."

"When we look at the risks that come with being infected, all the data say getting vaccinated is your safest way to combating the virus. I think it's tough to argue right now at all against vaccination."

"We can't think of all of these people [the vaccine hesitant or reluctant] as being people who just read something on the Internet and they haven't decided the virus isn't real."

"We don't have that one specific marker that says, 'OK, you have X amount of this antibody so that gives you Y amount of years or months of protection'."

Jason Kindrachuk, virologist, University of Manitoba

What we don't want people to say is: 'All right, I should go out and get infected, I should have an infection party'."

"Because somebody could die."

Michael Nussenzweig, immunologist, Rockefeller University 

A Jerusalem health care worker prepares a dose of the Pfizer-BioNTech vaccine designed to prevent COVID-19.  AHMAD GHARABLI/AFP via Getty Images

The most recent issue of the New England Journal of Medicine published a large new study out of Israel with the finding that while the Pfizer vaccine increases heart inflammation risk [three events per 100,000 vaccinated population], among people infected with the SARS-C0V-2 virus the risk becomes several-fold higher [11 cases per 100,000]. COVID infection as well was associated with a substantially increased risk of acquiring conditions or experiencing serious health impacts such as heart attack, blood clots and bleeding within the skull or brain.

Immunity, including protection against a breakthrough infection with Delta lasts longer following a natural infection as compared to immunity conferred by two doses of Pfizer, according to a preprint paper recently published, though no one is prepared to recommend COVID parties where groups of people gathering for the specific purpose of inviting infection to acquire a more robust immunity could conceivably lead to serious consequences, including death for some among the ill-informed and impetuous.

The coronavirus has had ample time to move within the global population where it continues to mutate and produce variants of concern, some acquiring increased transmission properties. Meanwhile, a study published by the U.S. Centers for Disease Control this week, established that the effectivenss of mRNA vaccines such as Pfizer and Moderna decreased from 91 prcent to 66 percent in front line workers, once the Delta strain became dominant. Leading the CDC to advise that the trend should be interpreted with caution.

 

People line up outside Canada Place for their COVID-19 vaccination in Vancouver in late June. Data shows 'breakthrough infections' after full vaccination aren't common, and experts say that means vaccines are doing their job. (Ben Nelms/CBC)

 

"As time since vaccination increases", says the CDC, protection too might be declining. Vaccines on the other hand, remain effective controls against serious health outcomes such as hospitalization and death. At the same time, ongoing reports of diminished immunity and breakthrough infections are hugely worrying, becoming the driver for debate over enhancing protection against the virus through the expedient of a third, booster dose of vaccine.

Of 680 people in Israel, hospitalized as a result of COVID-19, 331 of the total had been fully vaccinated. People over 60 with heart disease, lung problems or other underlying health issues are primarily represented among cases of severe breakthroughs, according to a Reuters report. And then there is the issue of context, lost in the reportage on social media of highly vaccinated populations seeing rising breakthrough cases.

The proportion of vaccinated among the infected increases resulting from the vaccines' inability to provide full protection against contracting the virus simply because the number of vaccinated in the population is steadily increasing. Even so, severe cases of COVID are rare among the vaccinated. That breakthroughs occur results from the fact that no vaccine can completely inure against infection; they can, however, be relied upon to protect from more serious conditions resulting.

The lesson is that the level of immunity should be tracked. Although inoculation can't entirely prevent acquiring COVID, those who are vaccinated will be less infectious and able to clear themselves of COVID more expeditiously than can those who remain unvaccinated; they also acquire milder infections.

"The only people that are really at risk are the unvaccinated. And, in certain provinces, we're taking very serious steps to protect the unvaccinated by preventing their exposure to the virus and the vaccinated population."

"It's sad that we have to go to the extent to do that, to protect the unvaccinated. But that is what is necessary in this situation, until we get them vaccinated."

Eric Arts, professor of microbiology and immunology, Western University

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